Displays which are used for example for monitors have to be through-illuminated or back-illuminated when using liquid crystal displays (LCDs) which themselves do not illuminate. For this purpose, typically cold cathode lamps or, in terms of miniaturisation and production of flat screens, flat optical fibres are used. Flat optical fibres as lighting surfaces mostly contain transparent plastic (e.g., PMMA, acryl, etc.) and at the side surfaces are supplied with light, for example by light-emitting diodes (LEDs). Above all, in a display having a lighting surface area which has a length across its diagonal of greater than 12 inches, there is the problem that a homogeneous illumination of the entire surface is no longer, or is hardly, possible. Above all, weaker illumination occurs in the centre of the display than in the remaining screen which means that inhomogeneous directional characteristic is to be observed. Furthermore, with conventional production devices for lighting apparatuses it is complex to produce lighting apparatuses of different sizes. The production of flat lighting apparatuses is a further difficulty as the size increases.